A metal coping is used in dentistry in the construction of a dental crown and bridge. The metal coping functions as the understructure of the crown and is usually covered, for reasons of aesthetics, with a fired-on coating of ceramic porcelain composition or an acrylic. The metal coping supports the coating and provides the required structural strength and rigidity for the restored tooth to resist the forces of mastication.
The customary practice is to cast the metal coping from an investment of a wax or plastic pattern of the tooth to be restored. The restoration formed using this procedure is conventionally referred to as a cast metal restoration. A metal coping has recently been developed for constructing a porcelain to metal crown which does not require waxing, investing or casting. The coping is formed from a prefabricated metal foil arranged in a prefolded configuration, with a plurality of foldable sections, as described in more detail, in U.S. Pat. No. Re. 33,099, which issued to applicant on Oct. 24, 1989. An alternative method of forming a dental coping from a metal foil is taught by applicant in U.S. Pat. No. 4,861,267, which issued on Aug. 29, 1989. In each instance, the starting material for forming the coping is a solid metal foil formed from a lamination of solid metal layers, each of a precious metal. The preferred arrangement is a lamination of layers of palladium disposed between gold or gold alloy layers, as taught by applicant in another U.S. Pat. No. 4,698,021 issued on Oct. 6, 1987. To form a coping from a preformed metal foil, the foil must be fitted and adapted to the die of the tooth to be restored and then swedged to conform to the die. The adaptation procedure is intended to be practiced by a dental technician in the dental laboratory and requires training and skill to achieve accuracy in getting a good fit at the margin.